Generally, smart grid is considered to be the future energy network that optimizes efficiency of operating the energy network through a bidirectional communication between supplier and consumer, while observing and controlling the energy network in real time using a combination of a related energy system and the information and communication technologies. Smart grid can be operated in association with new energy devices such as renewable energy generation system, electric vehicle charging system, and so on, which are recently increased, and since the energy consumption information of consumer is provided in real time, efficiency of using energy can be increased. Accordingly, the effect is provided, in which unnecessary investment for energy generation equipment can be saved, and emission of the greenhouse gases can be reduced. Recently, smart grid has been receiving increasing attention due to issues such as plans to modernize the energy network and expansion of the renewable energy, and the researches thereof are actively conducted.
The energy storage apparatus is one of the core technologies related with smart grids. The energy storage apparatus is aimed at balancing the loads, by storing the energy at off-peak time and using the stored energy at peak time. This energy storage apparatus can support efficient utilization of energy equipment.
Related technology mainly uses a pumped energy generation that converts surplus energy at night into potential energy of the water, or a chemical energy storage that combines a plurality of lead-acid batteries in series or in parallel.
However, since the pumped generation requires a sufficient amount of water, and also has strict conditions for the location thereof, it takes considerable cost for the construction thereof. Further, the lead-acid battery has a problem of low energy storage density, which restricts it from being configured for a high-voltage, high-capacity use.
Meanwhile, development of a lithium ion battery having a high energy storage density has recently enabled the establishment of the high-voltage, high-capacity energy storage apparatus with the chemical energy storage method.
The energy storage apparatus using the chemical energy storage method includes a battery module comprised of the lithium ion battery having high energy density, and a certain number of such battery modules are stacked in electrical connection in a battery rack formed in multi-stages.
Because such battery rack keeps therein battery modules, it is necessary that certain temperature and humidity are kept, good ventilation is ensured, and access to the stacked battery module for maintenance and repair is easy.
FIG. 1 is a perspective view schematically illustrating a related energy storage apparatus, and FIG. 2 is a cross-sectioned view of the energy storage apparatus of FIG. 1. Referring to FIGS. 1 and 2, the energy storage apparatus 1 includes a container 2, a battery rack 3, and a cooling member 4.
A plurality of battery racks 3 are positioned within the container 2. A plurality of battery racks 3 are adjacent to one sidewall and the other sidewall of the container 2, and disposed in parallel along a length direction of the sidewalls. Further, the cooling member 4 for cooling the heat generated from the battery racks 3 may be positioned within the container. The cooling member 4 may be necessarily provided for the maintenance and repair of the battery module.
However, the related energy storage apparatus 1 has following problems. When there is more number of the battery racks 3 positioned within the container 2, the energy density of the energy storage apparatus 1 may be further enhanced. However, since the cooling member 4 is positioned within the container 2, the number of the battery racks 3 provided within the container 2 is limited. Further, the limited number of the battery racks 3 may deteriorate energy density of the energy storage apparatus 1.
During cooling of the battery racks 3, heat may be generated in a process of cooling the cooling fluid having been used to cool the battery racks 3 with the internal cooling member 4. This heat serves as a cause of increased temperature inside the container 2. Accordingly, cooling efficiency of the battery racks 3 is deteriorated, and the cooling member 4 has to have an increased capacity, thus causing a problem that an area occupied by the cooling member 4 within the container 2 is increased.